Microstructure and thermoelectric properties of bulk and porous n-type silicon-germanium alloy prepared by HUP
Microstructure and thermoelectric properties of bulk and porous n-type silicon-germanium alloy prepared by HUP
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DOI：
10.1063/1.4731583
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发表时间：
2012-06
期刊：
影响因子：
2.1
通讯作者：
A. Kallel;G. Roux;T. Derycke;C. L. Martin;M. Marinova;C. Cayron
中科院分区：
文献类型：
--
作者：
A. Kallel;G. Roux;T. Derycke;C. L. Martin;M. Marinova;C. Cayron
通过对粉末制备和固结工艺的优化，在低升温速率下热压的n型硅锗（SiGe）合金中获得了较高的热电优值（ZT=1.25，800°C）。实验观察到HUP压实条件可以保持纳米结构化。我们还研究了孔隙率对热电性能的影响。多孔样品具有增强的塞贝克系数和低的热导率。然而，由于电导率的显著降低，块状样品的品质因数仍然优于多孔样品。除了通过致密化过程控制来限制纳米晶粒的生长之外，研究晶界工程以提高电荷载流子的迁移率似乎是一种有前途的方法。
The optimization of powders preparation and consolidation process leads to the achievement of a high thermoelectric figure of merit (ZT=1.25 at 800°C) in an n-type silicon-germanium (SiGe) alloy hot pressed at low heating rate. It has been experimentally observed that HUP compacting conditions can preserve nanostructuring. We also investigated the effect of porosity on the thermoelectric properties. Porous samples have enhanced Seebeck coefficients and low thermal conductivity. However, the figure of merit of the bulk specimen remains better than the porous samples due to a significant degradation of electrical conductivity. Working on grain boundaries engineering to enhance charge carriers mobility seems to be a promising way in addition to limiting nanograin growth with a densification process control.